I'll tell you what's more important than all the commentaries in your library: prayer.
Prayer is the preview of God's action.
If you think that the gospel is all about what we can do, that the practice of it is optional, and that conversion is simply something that anyone can choose at any time, then I'm concerned that you'll think of evangelism as nothing more than a sales job where the prospect is to be won over to sign on the dotted line by praying a prayer, followed by an assurance that he is the proud owner of salvation.
Sadly, there are some fine Christian people who believe that the only way to advance the gospel is to pray for revival and nothing else. You don't know if they have any non-Christian friends or if they have ever shared the gospel with anybody in the last 30 years. It's depressing going to prayer meetings like that. I don't want to pray like that.